Fixed Asset on Artwork

More info needed.

Is this a company asset that's been bought and hangs in the office, for example?

If so, it's an asset on the balance sheet (if it costs more than, say £300 - anything less than that I would expense).

Depreciate it at a rate appropriate to its estimated useful life. If it's not going to depreciate, then don't apply depreciation!

Investment is still an asset on the BS.

Annual revaluation exercise might need carrying out, as opposed to depn - I'd expect it wouldn't depreciate and hopefully apprciate in value!